(1) Field of the Invention
The present invention relates to an image processing support system, an image processing device and an image display device for correcting the characteristics of a display panel by performing processes for an inputted image signal so as to display the processed image signal as a visually satisfactory image in portable display apparatuses, such as a notebook personal computer, a PDA and the like.
(2) Description of the Related Art
With the improvement in the performance of personal computers (to be referred to as “PC(s)” hereinafter), an increased number of image signals have been handled in recent years by PCs via digital video/versatile discs (to be referred to as “DVD(s)” hereinafter), networks and the like. Such trend applies not only to desktop PCs, but also to portable notebook PCs. Furthermore, some personal digital assistants (to be referred to as “PDA(s)” hereinafter) which are smaller in size than notebook PCs also handle image signals these days.
However, since PCs are not originally intended for handling image signals, there is a fact that they are inferior to image display apparatuses including the television in terms of the image quality that they can offer. Images that notebook PCs can provide, in particular, are lacking brightness, colorfulness, and vividness due to reasons stemming from power consumption constraints, including that the backlighting of a liquid crystal panel used as a display device cannot be brightened much and that the color filter cannot be darkened as required because the brightness needs to be ensured while saving power consumption.
Under these circumstances, a satisfactory image quality for display is generally obtained by an image processing device that processes an input image signal and outputs such processed signal to a liquid crystal panel. In so doing, existing image processing support systems and image processing devices acquire an image signal, such as an RGB signal and a YIQ signal, and perform processes such as color correction and gamma correction for the image signal so as to carry out optical correction for a video camera, as well as nonlinearity correction for a display device and the like.
As examples of such image processing support systems and image processing devices for performing color correction, gamma correction and other processes, there exist an image processing support system and an image processing device, wherein the image processing device with a processor configuration such as that of a DSP (digital signal processor), for example, performs processing for an inputted image signal using software and an image processing support device (e.g., a personal computer) prepares a program executed on the DSP (Refer to Japanese Laid-Open Patent Application No.H10-243259 as an example).
There also exists another image processing device capable of improving visibility when low-brightness images, such as a scene including darkness in movie software and the like are reproduced, not only by performing gamma correction for an image signal in a gamma correction circuit, but also by raising input brightness levels at around white 25% or below, without correcting input brightness levels at or over white 50% (Refer to Japanese Laid-Open Patent Application No.H11-146232 as an example).
However, since such existing image processing support system and image processing devices are configured to perform processing in stationary apparatuses, it is difficult for them to be employed by portable devices, given such issues as power consumption and the scale of a device. Furthermore, since uniform processing is performed for an image signal without taking into account the characteristics of a display device, there is a problem that image quality of a sufficient level cannot be obtained.
Moreover, when a DSP is used as an image processing device and a program executed on such DSP is prepared in an image processing support system, there arises a problem that battery life is shortened and that a heavy battery with a large power capacity is required, when considering an object of achieving a colorful display screen by aggressively performing color enhancement for display devices with poor color reproducibility, such as liquid crystal panels employed by portable display devices including notebook personal computers and PDAs, since the DSP has drawbacks in terms of power consumption.
Furthermore, when changing the amount of correction to be made in gamma correction and other processes for an input brightness level simply on the basis of a fixed value, it is possible to determine a suitable fixed value used as a reference of correction depending on a display device, if only a specified type of display devices are employed. However, when a single image processing device needs to support multiple types of display devices, there is a possibility that image quality of a sufficient level cannot be achieved since a value suitable for the actual characteristics of a display device is not necessarily obtained.
The present invention has been conceived in view of the aforementioned problems, and it is an object of this invention to provide an image processing support system and an image processing device that are suited to be incorporated into a portable display device in terms of power consumption and the scale of a device, and that allow, even when more than one type of display devices are used, each of such display devices to have optimal brightness/color correction and enhancement, as well as allowing volume production of display apparatuses which incorporate such a display device and an image processing device as a set.